8YY old Bryant central AC. Moderately used, just popped it on last night a
nd I noticed even though the blower was running the condenser and fan outsi
de weren't. Tried each of three zones, that didn't make a difference. So
today I said what the hell, before I call the service guy I turned it on a
gain, fired right up. Too chicken to run it for more than a few minutes.
We've only had it on like once or twice this year, what might make it behav
e that way?
On Monday, May 18, 2015 at 6:22:20 PM UTC-4, noname wrote:
and I noticed even though the blower was running the condenser and fan out
side weren't. Tried each of three zones, that didn't make a difference.
So today I said what the hell, before I call the service guy I turned it on
again, fired right up. Too chicken to run it for more than a few minutes.
ave that way?
Ok tail between legs, for 9 years zone 3 only hasn't been turning on the AC
unit because the thermostat was wired wrong! Compared the wiring to the o
ther 2 zones and the yellow wire is connected to the wrong post (I think it
is Y1 or something).
Gonna switch it over tomorrow when I have better lighting. I don't have to
turn off the power do I ?
After switching your thermostat to Cool, it may wait several minutes
before it will signal the compressor to turn on. That's a safety feature
in some thermostats, to protect the compressor from being turned on too
soon after being turned off.
If I were going to fool with thermostat wires, I'd first cut the power
to the control unit so I wouldn't damage the compressor. (see above)
On Monday, May 18, 2015 at 9:25:37 PM UTC-4, J Burns wrote:
well it is clearly wired differently than the other two thermostats. How do I cut the power to the control unit is that the white box on the side of the furnance? Or should I just cut the power to the house?
In my breaker box, the breaker for the furnace/AC control is marked.
(There's another breaker for power to the compressor.)
There's also a light switch beside the furnace, to shut off power to the
control box and blower. If I remove the cover to the blower compartment
on my furnace, I can see the control box. An LED glows if it has power.
If your thermostats let you switch on the blower without heating or
cooling, you could use that to see if you switched off the right breaker.
It's called the process of elimination. Turn your breakers off, one by one, until the power to the "white box on the side of the furnace" goes off.
And for the love of God, label your damn circuit breakers.
HVAC techs the world around know who loves God,
the moment we start a job. We go glance into
the circuit box, and look for Sharpie marker.
Atheists and agnostics never label breakers.
Me, for example, I used three or four sharpies
to dryness in my panel box, I love God so much.
Wasn't sniffing solvent, honest!
-
.
Christopher A. Young
learn more about Jesus
. www.lds.org
.
.
On Tuesday, May 19, 2015 at 7:15:12 AM UTC-4, Stormin Mormon wrote:
Ok fixed the wiring for the 3rd zone. No luck! It seems Zone 1 turns on the AC just fine. Zone 2 and 3 the condenser fan never starts spinning. I verified they are all wired the same to the thermostats.
What next? Could this be the AC control unit? Any other debugging ideas?
On Wednesday, May 20, 2015 at 6:19:47 PM UTC-4, noname wrote:
I've never seen a multizone AC system, but I know they exist.
They key question would be how are these 3 separate thermostats
wired to the system? I would assume that they go into something
other than the normal one thermostat input that most ACs would have.
Would seem you need a controller of some kind before the AC unit
to work dampers to make the air flow go to the zone/s that need it
and not to the other zones. So, do the 3 thermostats feed into some
zoning gizmo?
The other thing that makes no sense is that you're saying that with
the non-working zones, the
blower starts up in response to the thermostat, but not the outside
condenser unit. I don't get that, unless some kind of zoning thing
is somehow involved. Single zone AC, the thermostat connects to
the controller on the air handler, which in turn has an output
that closes the contactor in the condenser, turning it on. I think
it all comes down to how this is wired and works, without a diagram
etc, impossible to diagnose.
I believe a compressor can be wrecked if not enough registers are open
in the house. Maybe the system wasn't designed to turn on the compressor
with zone 2 or zone 3 only, because because neither has enough
registers. There may be a diagram and explanation online for the OP's model.
On Wednesday, May 20, 2015 at 9:16:15 PM UTC-4, J Burns wrote:
I thought about that too. Like I said, I haven't seen a zoned
central AC system. The fact that you could only reduce airflow
so much with a typical system was a big problem. But now that
there are many dual stage compressors available, I would think
that may solve that problem. But IDK if they are doing that or not.
The essential problem here is what exactly are those thermostats
hooked up to and how? Air handler/furnace directly with the
zoning function built into the furnace? Never heard of that existing.
Or are they wired to some zoning controller before the AH/furnace?
I just came up with a third possibility. That the system isn't
really zoned at all. Those other two "zones" may just be thermostats
wired in to turn on the fan only. Like the upstairs gets too hot,
it turns on the system fan, to try to even out the temp. That
would explain why it works like it works. That's my bet.
It is very wise to turn off the power when
working on wiring. Thermostats are typically
24 VAC, not enough to really be dangerous. But
why risk damaging transformers, etc?
On Monday, May 18, 2015 at 5:22:20 PM UTC-5, noname wrote:
and I noticed even though the blower was running the condenser and fan out
side weren't. Tried each of three zones, that didn't make a difference.
So today I said what the hell, before I call the service guy I turned it on
again, fired right up. Too chicken to run it for more than a few minutes.
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